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Authors
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Tavana, H. ; Simon, F. ; Grundke, K. ; Kwok, D. Y. ; Hair, M.L. ; Neumann, A. W.
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Title
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Interpretation of contact angle measurements on two different fluoropolymers for the determination of solid surface tension
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Date
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14.10.2005
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Number
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13513
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Abstract
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Contact angle measurements with a large number of liquids on the semi-fluorinated acryl polymer EGC-1700 films are reported. The surface tension was determined to be <a name="mml20"></a><a style="text-decoration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6WHR-4G94HMX-1&_mathId=mml20&_cdi=6857&_rdoc=1&_ArticleListID=432781566&_acct=C000050221&_version=1&_userid=10&md5=a3ca3cf90ee3c12c300b67ac298c4ecd" title="Click to view the MathML source"><i>γ</i><sub>sv</sub>=13.84 mJ/m<sup>2</sup></a> from contact angles of octamethylcyclotetrasiloxane (OMCTS) and decamethylcyclopentasiloxane (DMCPS). Inertness of these two liquids makes them ideal for determination of surface tension of low-energy fluoropolymers. On the other hand, contact angles of many other liquids deviated somewhat fr<br />om a smooth contact angle pattern that represents the EGC-1700 surface tension. It is argued that noninertness of the molecules of these liquids gives rise to specific interactions with the polymer film, causing the deviations. Furthermore, contact angles of a series of <i>n</i>-alkanes (<i>n</i>-hexane to <i>n</i>-hexadecane) showed systematic deviations from this curve, similar to the trend observed for <i>n</i>-alkanes/Teflon AF 1600 systems studied earlier. Adsorption of vapor of short-chain liquids onto the polymer film caused their contact angles to fall above the <a name="mml21"></a><a style="text-decoration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6WHR-4G94HMX-1&_mathId=mml21&_cdi=6857&_rdoc=1&_ArticleListID=432781566&_acct=C000050221&_version=1&_userid=10&md5=1402c09b2c3b5f34cdcb6a7badd7cce2" title="Click to view the MathML source"><i>γ</i><sub>sv</sub>=13.84 mJ/m<sup>2</sup></a> curve, and a parallel alignment of molecules of the long-chain <i>n</i>-alkanes in the vicinity of the solid was the explanation for the deviation of their contact angles below it. It is found that vapor adsorption effect is more significant in the case of Teflon AF 1600, while the alignment of liquid molecules close to the surface is more pronounced for EGC-1700. <br></div><br><div style="margin-left: 25 !important; width: 600px !important"><h2>Graphical abstract</h2><p><br><img src="http://www.sciencedirect.com/cache/MiamiImageURL/B6WHR-4G94HMX-1-37/0?wchp=dGLbVzz-zSkzk" alt="Image" align="absbottom" border="0" height=178 width=362><br> Films of two fluoropolymers show very different properties upon contact with a liquid. Teflon AF 1600 is inert but EGC-1700 chains are reoriented.
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Publisher
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Journal of Colloid and Interface Science
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Wikidata
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Citation
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Journal of Colloid and Interface Science 291 (2005) 497-506
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DOI
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https://doi.org/10.1016/j.jcis.2005.05.001
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